This paper is the fourth in a series whose purpose is to study the interstellar abundances of sulfur, chlorine, and argon in the Galaxy using a sample of 86 planetary nebulae. Here we present new high-quality spectrophotometric observations of 20 Galactic planetary nebulae with spectral coverage from 3700-9600Å. A major feature of our observations throughout the entire study has been the inclusion of the near-infrared lines of [S III] λλ9069,9532, which allows us to calculate accurate S +2 abundances and to either improve upon or convincingly confirm results of earlier sulfur abundance studies. For each of the 20 objects here we calculate ratios of S/O, Cl/O, and Ar/O and find average values of S/O=1.1E-2±1.1E-2, Cl/O=4.2E-4±5.3E-4, and Ar/O=5.7E-3±4.3E-3. For six objects we are able to compare abundances of S +3 calculated directly from available [S IV] 10.5µ measurements with those inferred indirectly from the values of the ionization correction factors for sulfur. In the final paper of the series, we will compile results from all 86 objects, search for and evaluate trends, and use chemical evolution models to interpret our results. Table 1 lists the objects discussed in this paper. Column 1 gives the object name, column 2 the angular size, column 3 the slit offset, if any, and columns 4 and 5 the blue and red exposure times, respectively. Column 6 contains either K or C denoting optical/near-infrared spectrophometry obtained at Kitt Peak or Cerro Tololo, respectively.Six PNe have available ISO SWS observations that include the [S IV] 10.5µ line, which we discuss in §2.2; these objects are listed first in Table 1 and the ISO exposure times are given in the last column. Optical and Near-Infrared ObservationsObservations at CTIO were obtained in March 1997 using the 1.5m telescope and cassegrain spectrograph with Loral 1K CCD. The 1200 x 800 Loral 1K CCD has 15µ pixels.We used a 5 ′′ x 320 ′′ extended slit in the E-W direction. Perpendicular to dispersion the scale was 1.3 ′′ /pixel. Gratings #22 and #9 were used to obtain extended spectral coverage from 3600-9600Å with overlap in the Hα region. Both gratings have nominal wavelength dispersions of 2.8Å/pixel and 8.6Å FWHM resolution.Data for objects observed at KPNO were obtained in June 1999 with the Goldcam CCD spectrometer at the 2.1m telescope. The chip was a Ford 3K × 1K CCD with 15µ pixels. We used a slit that was 5 ′′ wide and extended 285 ′′ in the E-W direction, with a spatial scale of 0. ′′ 78/pixel. The 3700-9600Å range, overlapping coverage from ∼5750 -6750Å, was covered with two gratings. For the blue, we used #240 and a WG345 order-separation filter; wavelength dispersion was 1.5Å/pixel (∼8Å FWHM resolution). For the red we used grating #58 with an OG530 order-separation filter, yielding 1.9Å/pixel (∼10Å FWHM resolution). infrared extinction law, A(λ)/A(V) given by Rieke & Lebofsky (1985): for Brα and 10.5µ the values are 0.04 and 0.08, respectively. Combined with our value for c determined from the Balmer lines, we took c = 1.41E(B-V), and R, the r...

In this paper we present emission line strengths, abundances, and element ratios (X/O for Ne, S, Cl, and Ar) for a sample of 38 Galactic disk planetary nebulae (PNe) consisting primarily of Peimbert classification Type I. Spectrophotometry for these PNe incorporates an extended optical/near-IR range of λλ3600-9600Å including the [S III] lines at 9069Å and 9532Å, setting this relatively large sample apart from typical spectral coverage. We've utilized ELSA (Emission Line Spectrum Analyzer), a 5-level atom abundance routine, to determine T e , N e , ICFs, and total element abundances, thereby continuing our work toward a uniformly processed set of data. With a compilation

We have undertaken a large spectroscopic survey of over 80 planetary nebulae with the goal of providing a homogeneous spectroscopic database between 3600-9600 Å, as well as a set of consistently determined abundances, especially for oxygen, sulfur, chlorine, and argon. In the current paper we calculate and report the S/O, Cl/O, and Ar/O abundance ratios for 45 southern planetary nebulae (predominantly Type II), using our own recently observed line strengths published in an earlier paper. One of the salient features of our work is the use of the NIR lines of [S III] λλ9069,9532 coupled with the [S III] temperature, to determine the S +2 ionic abundance. We find the following average abundances for these objects: S/O=0.011±.0064, Cl/O=0.00031±.00012, and Ar/O=0.0051±.0020.

In this paper we present fully reduced and dereddened emission line strengths for a sample of 45 southern Type II planetary nebulae (PNe). The spectrophotometry for these PNe covers an extended optical/near-IR range from 3600 -9600Å. This PN study and subsequent analysis (presented in a companion paper), together with a similar treatment for a northern PN sample, is aimed at addressing the lack of homogeneous, consistently observed, reduced, and analyzed data sets that include the near-IR [S III] lines at 9069 and 9532Å. The use of Type II objects only is intended to select disk nebulae that are uncontaminated by nucleosynthetic products of the progenitor star. Extending spectra redward to include the strong [S III] lines enables us to look for consistency between S +2 abundances inferred from these lines and from the more accessible, albeit weaker, [S III] line at λ6312.Subject headings: ISM: abundances -planetary nebulae: general -planetary nebulae: individual (Cn2-1, Fg